This invention relates generally to methods and apparatus for monitoring patients. Conventionally, the monitoring of a patient such as in an intensive care unit of a hospital has required vigilant surveillance by one or more nurses. More recently, monitoring means have been utilized in the form of electrical monitoring and recording devices which are connected to the patient by suitable electrical wires. During surgical operations and during their stay in the ICU (Intensive Care Unit), patients are attached by cables to the monitoring or treatment equipment. Cabling, however, complicates the treatment process in many ways; for instance, cables obstruct nursing procedures and complicate transfers, as they have to be attached and detached. Such conventional devices have required that the patient's bed be made electrically shockproof. The use of such wiring limits the mobility of the patient and conventionally has required that the patient remain in the shockproof bed. Because of the high cost of the equipment and the installation, the use thereof has been primarily limited to intensive care units of hospitals and, thus, such monitoring has not been readily available in connection with less serious patient problems.
Ideally, sensors would be attached to patients only once, when they arrive at the hospital, and detached when they leave. It has been known in the prior art to use telemetric devices in connection with physiologic monitoring. One such device is shown in the Preston U.S. Pat. No. 3,212,496 which discloses a molecular physiological monitoring system wherein the voltage produced by the heart in the functioning thereof in sensed and transmitted to an EKG receiver and recording or display device. In Preston, the transducer system is implanted subcutaneously or externally.
Lewis' U.S. Pat. No. 3,943,918 discloses a throwaway, one-time use signal sensing and telemetric transmitting device for use such as in the care of medical patients requiring a monitoring of a physiological function such as the cardiac function of the patient. The device includes one-time use self-powering battery means, adhesive means for attachment of the device to the patient and electrodes for sensing the physiological functioning. A disposable cover is removed to expose the adhesive means and the battery means are actuated to power the device at the time of use. The radio frequency transmitted signal is received on a suitable radio telemetry receiver for monitoring and recording as desired.